Crash box

Abstract

A crash box for a motor vehicle includes an attachment portion which engages a longitudinal member of the motor vehicle and is secured thereto by at least one screw bolt which extends through a spacer sleeve. The spacer sleeve is securely fixed to the attachment portion and has two threaded portions of opposite pitch. Inserted from opposite sides of the spacer sleeve are tolerance compensating bolts, which are each provided with an inner rotary catch for interaction with an outer thread of the screw bolt. When the screw bolt is screwed in, the tolerance compensating bolts are thus moved apart until abutting against opposite inside wall surfaces of the longitudinal member. The screw bolt engages hereby a nut on an outside of the longitudinal member so that the attachment portion is now held without clearance on the longitudinal member by a head portion of the screw bolt and one of the tolerance compensating bolts, and by the other one of the tolerance compensating bolts and the nut.

1. A crash box for a motor vehicle, comprising:
 an attachment portion for engagement into a longitudinal member of the motor vehicle; 
 a screw bolt for connecting the attachment portion to the longitudinal member; 
 a spacer sleeve securely fixed to the attachment portion and having two threaded portions of opposite pitch; 
 tolerance compensating bolts for threaded engagement into opposite ends of the spacer sleeve, each of the tolerance compensating bolts provided with an inner rotary catch for interaction with the screw bolt such that the tolerance compensating bolts move away from one another, as the screw bolt is screwed in, until the tolerance compensating bolts abut against an inside wall surface of the longitudinal member so as to hold the attachment portion without clearance in relation to the longitudinal member. 
 
   
   
     2. The crash box of  claim 1 , wherein the rotary catch of each tolerance compensating bolt is constructed to disengage from the screw bolt, when the tolerance compensating bolt abuts against the inside wall surface of the longitudinal member and a maximum load is exceeded so that the tolerance compensating bolt can no longer rotate. 
   
   
     3. A method of securing a crash box to a longitudinal member of a motor vehicle, comprising the steps of:
 connecting a spacer sleeve, having two threaded portions of opposite pitch, to an attachment portion of a crash box; 
 screwing a first tolerance compensating bolt into one end of the spacer sleeve; 
 screwing a second tolerance compensating bolt into another end of the spacer sleeve; 
 placing the attachment portion into a longitudinal member; and 
 threading a screw bolt into the spacer sleeve to move the first and second tolerance compensating bolts in opposite directions against an inside wall surface of the longitudinal member so as to hold the attachment portion without clearance in relation to the longitudinal member. 
 
   
   
     4. The method of  claim 3 , wherein the tolerance compensating bolts are moved successively by the screw bolt. 
   
   
     5. A crash box for incorporation between a bumper cross member and a longitudinal member of a motor vehicle, said crash box comprising:
 an attachment portion for engagement into the longitudinal member of the motor vehicle; 
 a screw bolt for connecting the attachment portion to the longitudinal member; 
 a spacer sleeve non-rotatably connected with the attachment portion and having two threaded portions of opposite pitch; and 
 tolerance compensating bolts for threaded engagement in the spacer sleeve, each of the tolerance compensating bolts provided with an inner rotary catch which engages an outer thread of the screw bolt, when the screw bolt extends through the tolerance compensating bolts and the spacer sleeve, wherein the tolerance compensating bolts, when assembled, are brought into abutment against an inside wall surface of the longitudinal member as the screw bolt turns and engages a nut on an outside of the longitudinal member so that the attachment portion is held without clearance on the longitudinal member by a head portion of the screw bolt and one of the tolerance compensating bolts, and by the other one of the tolerance compensating bolts and the nut. 
 
   
   
     6. The crash box of  claim 5 , wherein the rotary catch is formed by a protrusion extending from an inside circumference of the tolerance compensating bolt and intended to lock onto the screw bolt. 
   
   
     7. The crash box of  claim 5 , wherein the attachment portion has receiving bores for accommodating the spacer sleeve. 
   
   
     8. The crash box of  claim 5 , wherein the nut is a cage nut. 
   
   
     9. The crash box of  claim 5 , wherein the attachment portion has pairs of opposite walls, wherein the walls of one pair have a depth which is smaller than a depth of the walls of another pair. 
   
   
     10. The crash box of  claim 5 , wherein the rotary catch is a plastic ring. 
   
   
     11. The crash box of  claim 10 , wherein the plastic ring is made of polyamide. 
   
   
     12. The crash box of  claim 5 , wherein the attachment portion has a width which is smaller than an inside width of the longitudinal member to thereby define a gap between the attachment portion and a confronting wall surface of the longitudinal member. 
   
   
     13. The crash box of  claim 12 , wherein the gap is about 3 mm in size. 
   
   
     14. The crash box of  claim 5 , wherein the attachment portion is part of a single-piece stop plate which rests upon an end flange of the longitudinal member, when assembled. 
   
   
     15. The crash box of  claim 5 , wherein the attachment portion is formed from the stop plate through debossing. 
   
   
     16. The crash box of  claim 14 , wherein the attachment portion is a tubular pipe connected through material union with the stop plate.